To prove the effectiveness of the protein of the present invention, specifically that of SEQ ID NO: 7, in its capability to block steroidogenesis, oogenesis and spermatogenesis in laboratory animals via GnRH immunoneutralization, the above mentioned protein generated and purified was inoculated into laboratory animals in quantities from 50 to 500 μg in an oil adjuvant, particularly the complete or incomplete Freund's Adjuvant or an experimental adjuvant, specifically chitosan. Various parameters were analyzed such as the capability of animals to develop antibodies against the protein, their reproductive activity, spermatogenesis, oogenesis and androgen levels.